Get the dirt on how to make your garden grow
From delicate ferns to succulent tomatoes, determining the best soil for different plants may seem like dirty work, but it’s worth it. Not all soil is created equal, and there's a good reason. Different plants have different soil requirements, so whether you’re cultivating indoors all winter or ready to sew your seeds for the summer, this guide will help you determine just what dirt you need for the job.
The Best Soil for Indoor House Plants
If you want your monstera to grow to monstrous size, it turns out the best soil for your houseplants isn’t soil at all. Ideally, your indoor plants sit in something called a “potting mix,” which is specific to indoor plants. This is a blend of very fine bark, peat moss, perlite, and vermiculite. Essentially, it’s what is called a planting medium and does not contain dirt. It offers excellent drainage, something critical to the health of houseplants.
Potting soil, on the other hand, is a potting mix with more dirt and other planting mediums. It’s not a great choice for indoor house plants because it will retain too much water, leading your plants to become overwatered and attracting the dreaded fungus gnats and other indoor houseplant pests. There are other even more specialized indoor planting mediums for cactus, African violets, terrestrial orchids, and epiphytic orchids.
The Best Soil for Outdoor Container Plants
Choose potting soil for any outdoor plants going into pots and planter boxes. This will be a mix of soil with a lot of perlite, vermiculite, and peat moss designed to help the soil drain fast enough to avoid getting the plant's roots soggy and causing root rot.
You want more soil in this situation because otherwise, your plants would dry out way too fast outside. Be sure it’s an outdoor potting mix, but not a planting mix. Remember that container plants typically require more fertilization than in-ground plants, as they leech nutrients faster.
The Best Soil for Raised Beds
The best soil for raised beds actually depends on your raised garden bed's style. Some raised garden beds are essentially outdoor planter boxes, raised high enough off the ground to make it easy to plant without having to kneel or lean over, making gardening more accessible.
Other raised beds are designed more like a flower bed, with a lower profile. Using bagged potting soil alone in larger raised beds is unnecessary and costly. In both cases, the soil does need to offer more drainage than an in-ground planting, but the nature of the raised bed will change the exact ideal soil requirements.
If your raised bed rises well above the ground:
For a raised bed that sits high up off the ground, especially if it does not rest directly on the ground itself:
Look for high-quality potting soil like you’d use for a container garden (potting soil).
If you have a large raised bed (more than 2 feet by 4 feet with a depth of 2 feet or more), consider mixing in a small bag of compost for additional enrichment.
If you have your own compost or leaf mulch, you can work that in with a hand trowel or shovel.
If your raised bed is lower to the ground:
You'll want a different combination for raised beds that sit directly on the ground.
You can find raised-bed mixes, making life easy-peasy, but not all outlets carry them.
Make your own by looking for a basic mix. Think, soil, compost, moisture, drainage.
Soil: a high-quality planting mix
Compost: your own or purchased, worm castings, manure, leaf mulch, etc.
Moisture retention: use peat moss, vermiculite, etc.
Drainage: you can use potting soil, perlite, etc.
The Best Soil for Veggies
Many gardeners plant their veggies in raised beds, so generally speaking, you can use the same formula for your veggies as you do for raised beds. However, you may notice at your local garden center, bags of soil from brands like MiracleGro, marked specifically for growing veggies and herbs. When there are designated beds in your garden just for vegetables, by all means, consider this soil for the job.
In truth, though, it’s not much different from a flower bed mix or raised bed mix. However, using this for your vegetables and herbs won't hurt. Usually, the difference in this blend is additional additives for moisture control (like vermiculite) to help keep plants from drying out as well as extra built-in fertilizer to help boost growth. Because veggies have a short growing season and shallow roots, this helps ensure success for many gardeners.
Pro Tip: Take note of the label: if you grow your veggies in a container, you want potting soil, not planting mix.
The Best Soil for In-Ground Planting
Whether you are looking to till your soil for a serious vegetable patch ala Mr. Macgregor or you want to build up some gorgeous flower beds, for in-ground planting you will want a well-balanced soil to ensure all of your garden dreams come true.
The ideal soil is rich and loamy, both nutrient-dense and well-draining.
Enrich your existing garden soil by adding hardy planting mix (do not use topsoil alone).
You can add it in bulk or bag.
This should contain plenty of compost and peat in the blend.
Add compost and mulch every season.
Depending on your soil composition, you may need to add additional manure or compost to balance out sandy soil or peat to counteract heavy clay.
Avoid using potting soil in the ground. Potting soil won’t harm the plants in any way, but it doesn’t have much benefit and is much more expensive than planting mix.
The Best Soil for Flower Beds
Use the same combination you would for any in-ground planting. As with veggies, you may see bags of soil at your local garden center specific to flowers. These are often geared toward annual blooms and have the same target in mind: a short growing season and shallow roots. There’s nothing wrong with blends, and they won’t harm your garden, but they aren’t a necessity. Think of soil blends as gardening aids.
The Best Soil for Lawns
The best soil for growing grass is a well-balanced, compost-rich garden soil that provides plenty of nutrients for your lawn throughout the growing season. It often has peat moss, compost, and rich garden soil with a balance of nitrogen, phosphate, and potash.
If you’re just starting out planting your lawn you can find a nitrogen-rich bag of “turf builder” soil ready to go that you can till into the soil. You can also create this with bagged planting mix and additional manure, compost, and mulch.
If you are going to reseed a lawn (especially a mostly-dead lawn), you will want to till the soil and add a mixture of compost, mulch, and garden soil to create the best growing conditions. Or, use garden soil that has added compost and manure.
The Best Soil for Filler
Don’t be tempted by relatively inexpensive topsoil costs; don’t mistake it for good garden soil. Topsoil is literally the top layer of soil and contains very few nutrients. It is not good for any kind of direct planting and often used in combination with enriched soil and compost.
It works best to fill in landscape beds where you are adding hardscaping—don’t use it to plant directly in. Gardeners sometimes use it to fill in the base of something like a deep raised bed, but it’s important to find out the source of your topsoil before considering using it in any edible garden or even where you might put a fruit tree. It may come from a river bed or pond, but it may also come from a job site.
Other General Dirt Tips
There are some simple, tried-and-true tips to ensure you have the best soil for your plants.
Test your soil in early spring to see what type of pH balance it has. Aim for a pH level between 5 and 7.
Adjust your amendments based on the current needs: your soil may be either too acidic or too alkaline.
Acidic soil can balance out with lime; you can balance out alkaline soil with sulfate.
If you have sandy soil, amend the soil with manure, compost, or leaf mulch.
If you have clay soil, amend the soil with a rich mix that includes some peat, compost, and mulch. Work this deep into the ground and regularly aerate to avoid compaction.
Most bagged garden soil contains some compost, manure, and other enriching materials, but you can mix in additional compost to make richer soil.